conformational toggling of yeast iso-1-cytochrome c in the oxidized and reduced states构象的酵母iso-1-cytochrome c氧化和减少切换状态.pdf

Conformational Toggling of Yeast Iso-1-Cytochrome c in the Oxidized and Reduced States 1. 2.¤ 1 1 2 3 Wenxian Lan , Zhonghua Wang , Zhongzheng Yang , Jing Zhu , Tianlei Ying , Xianwang Jiang , Xu 3 1 3 2 1 2 Zhang , Houming Wu , Maili Liu , Xiangshi Tan , Chunyang Cao *, Zhong-Xian Huang * 1 State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China, 2 Chemical Biology Laboratory, Department of Chemistry, Fudan University, Shanghai, China, 3 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China Abstract To convert cyt c into a peroxidase-like metalloenzyme, the P71H mutant was designed to introduce a distal histidine. Unexpectedly, its peroxidase activity was found even lower than that of the native, and that the axial ligation of heme iron was changed to His71/His18 in the oxidized state, while to Met80/His18 in the reduced state, characterized by UV-visible, circular dichroism, and resonance Raman spectroscopy. To further probe the functional importance of Pro71 in oxidation state dependent conformational changes occurred in cyt c, the solution structures of P71H mutant in both oxidation states were determined. The structures indicate that the half molecule of cyt c (aa 50–102) presents a kind of ‘‘zigzag riveting ruler’’ structure, residues at certain positions of this region su